Skateboards and scooters utilizing trucks with hangers, kingpins, and base plates are known in the art. Skateboards generally have a pair of trucks mounted in opposing orientation to the underside of a board, either attached directly to the board using truck base plates or attached to the board through truck blocks. Generally, a skateboard style truck includes a hanger, a hanger pivot, a kingpin, and a pair of wheels. The hanger includes a race for the wheel axle and bearings. The hanger pivot permits the hanger to rotate the wheels and axle in the plane of the wheels and axle. The kingpin intersects the hanger approximately perpendicular to both the pivot axis and the wheel axle. In basic operation, when a skateboard or scooter rider leans to one side or the other, causing the board to tilt, the hanger pivot and kingpin, acting together, cause the hangers, and therefore the wheel axles, to rotate in the plane of travel. This rotation of the axles, in opposite directions, causes the board to turn, with the radius of the turn determined by the amount of rotation of the axles in the plane of travel—the plane of travel being a plane containing the contact points of the wheels. In this manner, a certain angle of tilt left or right will result in a corresponding turning radius. Changing the vertical angle of the truck in relation to the board (i.e. within the plane normal to the board and bisecting the board lengthwise) changes the orientation of the hanger and kingpin in relation to the board, thereby changing the amount of rotation of the wheel axles in relation to a given angle of board tilt. The effect is that a skateboarder may vary the responsiveness of the skateboard by varying the vertical angle of one or both trucks in relation to the board.
Scooters often have either a pair of opposingly oriented trucks with kingpins, as with skateboards, or a combination of one truck, with a kingpin, and a steerable single-wheel or double-wheel truck controlled by an attached vertical handle. In operation, tilting a scooter to one side or the other causes the skateboard-style trucks to operate in the same manner as described for the skateboard, above.
Trucks where the hanger and kingpin are constructed as a single piece, using elastomeric materials, are also known. In operation when the board to which these single-piece trucks are attached tilts left or right, the truck deforms to rotate the wheel axles within the plain of travel in substantially the same manner as trucks with separate hanger, hanger pivot, and kingpin parts. These single-piece trucks are generally mounted in the same manner as conventional trucks.
Devices providing the ability to vary the angle of the hanger and kingpin are therefore known, but are inconvenient to use and cause other undesired changes in performance. The following represents a list of known related art:
Reference:Issued to:Date of Issue:U.S. Pat. No. 6,896,274LeslieMay 24, 2005U.S. Pat. No. 4,251,087HansenFeb. 17, 1981U.S. Pat. No. 4,159,830SolimineJul. 3, 1979U.S. Pat. No. 4,089,536LarruceaMay 16, 1978U.S. Pat. No. 4,060,253OlendorfNov. 29, 1977U.S. Pat. No. 3,442,523ButlerFeb. 1, 1967U.S. Design Pat. No. 478,643LangfordAug. 19, 2003U.S. Design Pat. No. 302,993HeiligAug. 22, 1989U.S. Design Pat. No. 252,347SolheimJul. 10, 1979U.S. Design Pat. No. 252,346SolheimJul. 10, 1979
The teachings of each of the above-listed citations (which does not itself incorporate essential material by reference) are herein incorporated by reference. None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed.
U.S. Pat. No. 6,896,274 to Leslie teaches a skateboard with an arched board, bumpers extending forward and aft beyond the wheels, and foot straps. Leslie also teaches advantages of lowering the center of gravity of the board by lowering the center section of the board, in order to replicate the feel of a snowboard.
U.S. Pat. No. 4,251,087 to Hansen teaches using a trucks mounted to a base plates the bottom side of a skateboard allowing adjustment to pre-determined angles using co-axially installed angled wedges, or using a pivoting base plate with a hinge and cotter bolt. Changing the incidence angle of the hanger pivot angle and kingpin requires either replacing the angled wedges (which requires disassembly of the truck) or removing and reinstalling the locking bolt of the hinged base plate mechanism. The methods taught in Hansen require access to the bottom of the skateboard and tools to accomplish adjustments. Use of the pivoting base plate of Hansen introduces mechanical play from the base plate hinge and cotter bolt mechanisms into to the steering and suspension system, with consequent increase in vibration or wobble at higher speeds, and less precise response in tight turns.
U.S. Pat. No. 4,060,253 to Oldendorf teaches use of angled wedges as truck to pads to mount between the trucks and the bottom of the board in order to change the turn radius of the board. Use of angled wedges, as taught in Hansen and Oldendorf, does not allow for user-determined minor adjustments and requires disassembly of the trucks and consequent realignment when replaced.
U.S. Pat. Nos. 4,159,830; 4,089,536; and 3,442,523 to Solinine, Larrucea, and Butler, respectively, teach methods for tuning the responsiveness of the trucks to turning forces. The listed design patents teach various shapes for skateboards, including boards with lowered center sections and with extensions forward and aft beyond the wheels.
All of the known methods for changing the hanger and kingpin angle share common disadvantages: (1) the adjustment mechanisms are necessarily located underneath the board, making them inconvenient to adjust; (2) adjustment means requiring disassembly of the truck assemblies; (3) altering the hanger and kingpin angle also changes the height of the board deck, thereby changing the vertical center of gravity and causing undesirable changes in stability characteristics; (4) the hanger and kingpin can only be adjusted to pre-determined angles; and, (5) the range of adjustment is limited by the clearance underneath the board.
Thus, while the foregoing body of art indicates it to be well known to have a means for adjusting the angle of the trucks, including hangers and kingpins, of a skateboard to vary the turn radius, the art described above does not teach or suggest a board which has the following combination of desirable features: (1) adjustment means accessible by the user from above the board; (2) the ability to adjust hanger and kingpin angle without significantly changing the vertical center of gravity; (3) the ability to adjust kingpin angle in fine gradations; (4) adjustment range not limited by clearance under the board; (5) adjustment requiring no tools or minimal tools to adjust; (6) an hanger and kingpin angle adjustment apparatus installed on a board with lowered center section; and (7) quick and easy changing of truck and wheel assemblies from one skateboard to another.